[gpdriver17]

My 328i seems to have a massive understeer mid/late corner. Turn in it rotates nicely with the right technique. How are you guys addressing this? suspension modifications? Or just alignment? I know understeer isn't a bad thing, but I'd like it to be balanced enough that it's possible to make the car rotate with throttle/lift off.

[ClevelandBeemer]

Originally Posted by gpdriver17

My 328i seems to have a massive understeer mid/late corner. Turn in it rotates nicely with the right technique. How are you guys addressing this? suspension modifications? Or just alignment? I know understeer isn't a bad thing, but I'd like it to be balanced enough that it's possible to make the car rotate with throttle/lift off.

Camber, camber, camber.

The factory camber spec is not great for competitive track use. To truly address this issue you are going to go wayyyyyyy down the rabbit hole of suspension mods. If you plan on daily driving your 328i most of the needed suspension mods will take away from a relax daily driving experience.

If you were to start changing things you need to first look at suspension geometry and front camber. However, camber is not enough. You should really consider the following:

PATH 1

Adjustable coil overs (gives you complete control of ride heights, significantly reduces body roll, keeps wheels on the ground, and reduces brake dive)
Upgraded sway bars (works in concert with the coil overs)
Strut bracing front and rear
Camber plates (best adjustability, worst daily drivability)
Wider wheels (9"+ to fit at least 245's or 255's up front)
More sticky tires (200 treadware or less)
A limited slip differential (better control and corner exit)

You will need all of the above mods in order to have a package that works well. There are lots of posts in the suspension and track sections of the forum that can lead you in the right direction. However, from a daily driving standpoint this will create a twitchy car that will transmit more road noise in the cabin, will be transmit every little bump, will be very harsh over large bumps, and will wear through tires unevenly. Not great if you do 10,000+ highway miles a year.

PATH 2

If you are going to daily I would suggest the following:

Get the M3 lower control and upper thrust arms (ONLY IF YOU ARE RWD) This will give you more camber without the noise of camber plates while also preventing wheel rub. See link below.

Upgrade to a limited slip differential. This will eliminate mid corner one wheel peels and significantly reduce lap times as a result. (you will only see laptime reduction if you are currently running into mid-corner traction issues on power) As a result you will have better turn in and better rotation on corner exit. As a happy bonus you will have significantly better acceleration in wet or snowy conditions.

(OPTIONAL) Finally coilovers. They will make a huge difference of how the car behaves throughout all parts of cornering, especially in combination with upgraded sway bars. However, they will also make the largest negative impact to daily drivability if you go too aggressive or poor quality. KW and Bilstein are great places to start. (Look at the suspension section of the forum for recommendations).

Final thoughts: Consider one of the two paths. Either one will solve your issues depending on your use case. Many will say just throw on more sticky tires but this is a half measure. With track duty you will more than likely delaminate the tread near the sidewall due to in adequate camber.

Good luck.

Edit: A final final thought. You could simply do a tire upgrade only. This will make an immediate impact on the driving characteristics of the car. However, I do not recommend this because if you do not have the proper suspension setup, i.e. enough camber, then you will cause the tires to delaminate in as little as one 20 min track session. If you only plan to autocross then tires only will be fine.

https://www.bimmerworld.com/Suspensi...Assembled.html

[alohasurftoad]

what wheels, tires and suspension do you currently have?

[Polo08816]

Originally Posted by ClevelandBeemer

Camber, camber, camber.

The factory camber spec is not great for competitive track use. To truly address this issue you are going to go wayyyyyyy down the rabbit hole of suspension mods. If you plan on daily driving your 328i most of the needed suspension mods will take away from a relax daily driving experience.

If you were to start changing things you need to first look at suspension geometry and front camber. However, camber is not enough. You should really consider the following:

PATH 1

Adjustable coil overs (gives you complete control of ride heights, significantly reduces body roll, keeps wheels on the ground, and reduces brake dive)
Upgraded sway bars (works in concert with the coil overs)
Strut bracing front and rear
Camber plates (best adjustability, worst daily drivability)
Wider wheels (9"+ to fit at least 245's or 255's up front)
More sticky tires (200 treadware or less)
A limited slip differential (better control and corner exit)

You will need all of the above mods in order to have a package that works well. There are lots of posts in the suspension and track sections of the forum that can lead you in the right direction. However, from a daily driving standpoint this will create a twitchy car that will transmit more road noise in the cabin, will be transmit every little bump, will be very harsh over large bumps, and will wear through tires unevenly. Not great if you do 10,000+ highway miles a year.

PATH 2

If you are going to daily I would suggest the following:

Get the M3 lower control and upper thrust arms (ONLY IF YOU ARE RWD) This will give you more camber without the noise of camber plates while also preventing wheel rub. See link below.

Upgrade to a limited slip differential. This will eliminate mid corner one wheel peels and significantly reduce lap times as a result. (you will only see laptime reduction if you are currently running into mid-corner traction issues on power) As a result you will have better turn in and better rotation on corner exit. As a happy bonus you will have significantly better acceleration in wet or snowy conditions.

(OPTIONAL) Finally coilovers. They will make a huge difference of how the car behaves throughout all parts of cornering, especially in combination with upgraded sway bars. However, they will also make the largest negative impact to daily drivability if you go too aggressive or poor quality. KW and Bilstein are great places to start. (Look at the suspension section of the forum for recommendations).

Final thoughts: Consider one of the two paths. Either one will solve your issues depending on your use case. Many will say just throw on more sticky tires but this is a half measure. With track duty you will more than likely delaminate the tread near the sidewall due to in adequate camber.

Good luck.

https://www.bimmerworld.com/Suspensi...Assembled.html

One addition to this with a caveat. I ended up also installing the BMW camber correct wheel hubs for an additional -0.5. It will not add any NVH and if you're going to do this, you might as well replace your front wheel bearings while you're at it. There is a downside though. This will slightly reduce the clearance to the strut body between your wheel/tire as opposed to a camber plates.

[jmg]

A bit of trail braking.

[gpdriver17]

Originally Posted by alohasurftoad

what wheels, tires and suspension do you currently have?

Everything is stock. Tires are eco drive? Some pos a used car dealer put on, cheapest thing they could find.

[Desertnate]

Originally Posted by ClevelandBeemer

With track duty you will more than likely delaminate the tread near the sidewall due to in adequate camber.

Good luck.

I can attest to this. The delamination of a set of tires while autocrossing is what drove me to start a similar thread in this section of the forum.

My outer tread blocks are taking a beating and I have to run really high tire pressures to keep my front tires off the sidewalls during each run.

[alohasurftoad]

Originally Posted by gpdriver17

Everything is stock. Tires are eco drive? Some pos a used car dealer put on, cheapest thing they could find.

do you have 18's, 19's, staggered or square? base suspension or 704? is this for specifically track or a daily+ocnl track?

everyone's camber recommendations are fine but imo i'd start with increasing the front tire width and better tires. i'd expect the described understeer if tracking with eco-drive and 225's up front.

i'd get a decent spring/damper setup or coilovers next. something to add a lot of -camber is fine for mostly track but understand that -camber for track is not good for daily driveability and tire wear.

Polo08816 has covered literally everything can possibly get. how "deep" are you planning on going this and what is your budget?
.

[jmg]

Originally Posted by gpdriver17

Everything is stock. Tires are eco drive? Some pos a used car dealer put on, cheapest thing they could find.

How much experience do you have?